Speed-changing mechanism.



B. GMR.

SPEED CHANGING MEGHANISM.

APPLICATION FILED JULY 8, 1907. 912,559. Patented @10.16, 1909.

2 STBETS-SHEET l.

26` v LEM W 25 I E i 1 L Q 273 32" 24 2123 r A 5 5 i; Il l v 3 "H If 'H"IHMIHH. li I I: I L im Ill l 2 y y' h: Y, I I 22 l .M ll i IR r I o d;

2 I my; WL'lnesse-s Lawaai..

MQW/WM (2%,

BERTHOLD GMR, OF SCHNIS, SWITZERLAND.

SPEED-CHANGIN G MECHANISM.

Specification of Letten Patent.

Patented Feb. 16, 1909.

Application led July 8, 1907. Serial No. 882,710.

To all 'whom 'it may concern:

Be it known that I, BERTHOLD GMR, a citizen of the Republic ofSwitzerland, residing at Schnis, in the Canton of St. Gall, Switzerland,have invented certain new and useful Improvements in Speed-ChangingMechanism; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to figures ofreference marked thereon, which form a part of this specification.

Gearing having two smooth cone pulleys with a belt or the like passingover` them, which, for the purpose o f changing the speed of revolutionof the driven shaft, can be shifted in the axial direction of thepulleys, a tension-device for the belt being provided, is well known.Such gearings, have the disadvantage, however, that in order to attaincertain and regular transmission, definite proportions must bemaintained, lying between certain limits. Thus, for instance, the twocone pulleys must be of approximately the same diameter, and between thetwo axes there must be maintained a sufficiently great distance. Thebelts in these prior devices are tightened by hand or by positive means,and without reference to alterations in length caused, for instance, bychanges in the degree of moisture and in the temperature of the air; andfurther ence to unequal stretching of the belts, which results withvariable tension, so that the transmission of motion is not uniform, andit is diiiicult to keep the belts taut unless the distance between theaxes of the pulleys is considerable and the latter are of about the samemiddle diameter.

According to my invention permanently regular transmission of motion isinsured by the binder pulley of the tightening-device automaticallycompensating any changes in the length of the belt.

Several forms of construction of the invention are illustrated in theaccompanying drawings.

Figure 1 is an elevation of the first form, employed indriving anembroidering machine, only a portion of which is shown.

without referi Fig. 2 is a lan of Fic'. 1. Fig. 3 is a side elevationof) Fig. 1. F ig. 4 is a section on the line A-A of Fig. 3. Figs. 5 and6 show, on a. larger scale, in section and plan, details of parts to behereinafter referred to. Fig. 7 illustrates a second form of the device,and Fig. 8 a third form thereof.

Referring more particularly to Figs. 1-6, 1 designates one of thestandards of a shuttle embroidering machine, 2 a countershaft pulley,connected by gears with the main shaft 3 of the machine, and 4 apattern-hoard secured to an upright 5. Between the upright 5 and thepulley 2 there is mounted a rectangular rocking frame 6, turning on thebase-plate 7. This frame carries an electric motor 8, on whose shaft,whichv revolves at constant speed, there is mounted a cone belt pulley9. Above the motor shaft there is mountedv parallel therewith in theframe 6 a second shaft carrying another cone belt pulley 10, adjacent towhich a cylindrical belt pulley 11 is also secured on the shaft. The twopulleys 9, 10 are mounted the reverse way to each other on their shafts,and

the pulley l0 1s of approximately three' times the middle-diameter ofthe pulley 9. The pulleys are connected by an endless belt 12, whichpasses over them, while a similar belt 13 connects the ulley 11 with thepulley 2. The frame 6 is eld on the one slde by the belt 13 and on theother side by a spring 14, which draws it toward the upright 5 and thuscauses tightening of the belt 13 (Figs. 1 and 2).

On a spindle 15, directed similarly to the facing generatrixes of thetwo pulleys 9, 1() (though it might be directed parallel to the axes ofthe two pulleys), there is mounted a bell-crank lever 16, 17 having anelongated hub which slides on the spindle. In

j the upper end of arm 16 of said bell-crank lever is swiveled a fork 18in which is jour naled a flanged binder-pulley or idler 19. The latteris pressed against one side of the belt 12 by a spring 20, secured tothe top of the frame 6, and drawing upon the arm 17 of the bell-cranklever; while the other half' of the belt is located between the outerends of the fork 18, which projects beyond the axis of the idler 19. Thebelt 12 is thus guided between the fork-Shanks d the idler-flanges(Figs. 1 and 4). With the hub of the lever 16, 17 there is connected anendless rope 21 (e. g. a thin wire rope), which passes overguide-pulleys 22, 23, 24, to a drum 26, provided with a handwheel andturning on a spindle 25 of the embroiderlng machine. The rope is passedseveral times round the drum to prevent independent movement. Theportion of the rope 21 lying between the pulleys 22, 23 and connectedwith the lever 16, 17 lies parallel to the rod 15 (Fig. 3). The operatorcan reach the hand-wheel of the drum 26 from his place before thepattern-board 4 and by rotating the wheel, can with the aid of the rope21 and belt-fork 18, shift the belt 12 forward or backward on thepulleys 9, 10, and thus cause the main shaft 3 of the machine to makethe desired number of revolutions. The idler 19, under the influence ofthe spring 20, will always be pressed against the belt 12, and thus keepit taut. Since the arcs of the pulleys 9, 10 which are embraced by thebelt 12 are at the same time increased, slipping of the belt isprevented and uniform transmission of motion insured. This regulation ofthe number of revolutions of the shaft 3 is effected during the ordinaryeinbroidering procedure, by the so-called festoon-lever 2i, which ispivotally vsecured to the standard 1, occupying the fullline positionshown in Fig. 1. The oiiice of this lever, as is Well known, is, on itsoperation by hand, to throw into operation mechanisms other than thoserequired for ordinary embroidering, whereby so-called ""festooning7 isperformed, during which work the shaft 3 must rotateat the lowest speed.In order, that the lever 27 on being actuated may also effect shiftingof the belt 12 011 the pulleys 9, 10, so that the speed necessary forfestooning may be obtained, the following arrangement is adopted. Thefront end of the lever 27 has a forked extension 28, projecting beyond'its lateral handle, and has also a laterally-protruding pin 29 (Fig.6). The fork 28 embraces a sleeve 30, which incloses the vertical lengthof rope 21 extending from the one pulley 24E to the drum 26. This sleeveis provided with end-pieces 31, 32 to afford it guidance on the rope,the top piece 32 being, moreover, flanged. lVithin the sleeveis a piston33, which is secured to the rope 21 and serves as a stop. Between thepiston 33 and bot` tom piece 31 is a spiral spring 34, which tends tokeep the sleeve in such position that the head 32 bears upon the piston33 (Fig. 5). On 'the spindle 25, and adjacent to the drum 26, there issecured an arm, on which is mounted a three-armed level' 35, one arm ofwhich is drawn against the flange of the drum 26 by a spring 36. `Thedownwardly directed lever-arm presents a hook 37, which projects intothe path of the pin 29 of the'lever 27. When the lever 27 1s turnedupward into the dotted-line position in Fig. l, for the purpose ofstarting festoo'ning,the fork 28 will draw the sleeve 30 upward, thespring 34 being compressed,

and finally the rope 21 will follow through the action of the spring.The belt 12 will thus be'pushed by the fork 18 toward the one end (inFig. 3 the left end) of the pulleys 9, 10, and the slowest speedtransmitted to the shaft 3. The lever 27 and sleeve 30 are maintained intheir uppermost position by the pin 29 of said lever snapping into thehook 3( of the lever 35, in which it is retained by the action of thespring 36. The spring 34 acts as butter, so that on sudden operation ofthe lever 27, the rope 21 may not be jerked up with it, but is causedgradually to ascend. i

Instead of the idler 19, another belt tightening-device may be employed,which, however, with an open belt should be capable of more tightlydrawing the latter, as the arcs of the cone pulleys embraced by the beltare smaller with these devices. Figs. 7 and 8 illustrate two suchdriving-devices with cone pulleys, provided with tighteningappliances ofother descriptions. 1n each construction the two superposed cone pulleys9, 10 are, as before, mounted in a rocking frame 6, turning on abase-plate 7 The frame is held in vertical position by the action of aspring 14 on the one side, and on the other side by the belt 13 passedround the pulley 11. The lower smaller cone pulley 9 issecured on theshaft of an electric motor 8, mounted in the frame 6, while 18 is a forkfor shifting the belt on the cone-pulleys. In the construction showninFig. 7, the shaft carrying the upper cone pulley 10 and the belt pulley11 is mounted on levers39(merely diagrammatically indicated in thedrawing) turning at 38 on the frame 6, and the belt 12 is tightened bythe pull of the spring 14, which in endeavoring to rock the fr ame 6 onits fulcrum, causes the lever 39with cone pulley 10 and belt pulley 11to move in the direction of the arrow, whereby in addition tothe beltl2, the belt 13is also tightened. 1n the construction illustrated inFig. 8, the shaft carrying the cone pulley 10 and the pulley 11 ismounted on arms L10 which turn at 41 on the frame 6 and are drawn uponby a spring 42, which has the tendency to turn the arms with cone pulley10 and pulley 1.1 upward, and thus tighten the. belt 12. The latter iscrossed over the cone lpulleys 9, 10, though Y it might be an open belt,in which case a belt fork of the kind shown in Fig. 7 would be employed.-In similar manner, the belt 12 in Fig. 7 might be crossed as shown inlthe frame, means to rock the frame away shifting device movablelongitudinally of constructions may slide parallel with thc axes of thetwo cone pulleys, erpara'llel with the facing generatrixes ofthe same,and they may be shifted, for instance, by meansv of a rope in themannerillustrated i-n Figs. 1-4. To prevent injury to the belt, the one orboth arms of the belt fork may be furnished with a pulley 43, to engagethe belt.

Thus with al1 the above forms of construction of the new driving-gearwith cone pulleys, by the provision of a tighten'- ing-deice for thebelt, regular and certain transmission of motion is insured, evenalthough the two cone pulleys may be arranged at the smallest distanceapart. The entire apparatus, therefore, can be fixed in a very limitedspace.

The draw-springs 14, 20. 42, might be replaced by pressing-springs, orby weightsI` or magnetic influence might be made use of.

Having now particularly described andi ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. In a speed changing mechanism the combination with two cone pulleysand a belt connecting the same, of a rockable frame supporting thepulleys, means on the frame for shifting the belt, and automaticallyoperated means for maintaining the belt in a i taut condition. r

2. In a speed changing mechanism, the combination with two cone pulleysand a belt connecting the same, of a belt-shifting device movablelongitudinally of the pulleys, and a single tension member carried bythe shifting device automatically positionable to the incline of thebelt.

3. In a speed changing'mechanism, the combination with two cone pulleysand a belt connecting the same, of a swiveled beltthe pulleys and atension member journaled in said device whose axis is capable of beingpositioned at an angle to the axes of the pulleys.

' 4. In combination, a rocking frame, pulleys supported thereby, a beltconnecting two of said pulleys, a pulley journaled independently of theframe. a belt connecting the last named pulley with one of the pulleysof frpm the independently journaled pulley,

and means to tension the rst named belt.

In a speed changing mechanism, thef' combination with two smooth conepulleys and a belt connecting thc same, of a shaft g' mounted sultai1ti:1lly parallel to the facl in;r generatrixes of the cone pulleys,a beltl shifting member slidably mounted on the shaft, a flanged idlercarried by the belt I shifting member whose axis is capable of beingpositioned at an inclination to the axes of the pulleys, and means toautomatically press the idler against the belt.

6. In a speed changing mechanism the combination with two cone pulleysand a belt connecting the pulleys, of a fork for shifting the belt, anidler carried by the fork, means for automatically resiliently pressingthe idler against the belt, a rotary drum, a iexible member connectingthe fork and drum, and a stop resiliently connected with the flexiblemember, in combination with a machine operating lever adapted to engagethe stop.

7. In a speed changing mechanism, the combination with two cone pulleysand a belt connecting the same, of a fork for shifting the belt, anidler carried by the fork, means for resiliently holding the idler incontact with the belt, a rotary drum, an endless connecting memberconnecting the fork and drum, a sleeve surrounding the connectingmember, a spring in said sleeve having one end connected to the sleeveand its other end connected with the connecting member, in combinationwith a machine operating lever adapted to raise the sleeve,

and thereby move the connecting member its raised position.

8. In a speed changing mechanism, a rockable frame, a motor mountedthereon, a cone pulley7 carried by the motor shaft, a cone pulleyjournaled in the frame above said motor shaft, a belt connecting thepulleys, a support on the frame longitudinally of the pulleys, a bellcrank lever slidable on the support, a fork on one arm of the bell cranklever inclosing the running on and running olf portions of t-he belt, anidler journaleel in the fork in engagement with one portion of the belt,and a. spring connected to the other arm of the bell crank lever to holdthe idler in position.

9. In a speed changing mechanism, a pivoted frame, a motor mountedthereon, a cone pulley carried by the motor shaft, a cone pulley journaled in the frame above the aforesaid pulley, a belt connecting thepulleys, a support on the frame substantially parallel to the facinggeneratrixes of the pulleys, a bell-crank lever slidable on the support,a fork swiveled' in one arm of the bell-crank lever inclosing` therunning on and running otf portions of the belt., a flanged rollerjournaled in the fork engaging one portion of the belt, a spring bearingon the other arm of the bell crank lever, a drum. a flexible memberconnecting the drum and bell crank lever, pulleys for guiding thelexible member, a sleeve surrounding the flexible member, a slide in thesleeve connected to the latter` a stop in the sleeve, a spring betweenthe slide and stop, in cornbination with a machine operating lever, afork on the latter to engage the sleeve and thereby move the fiexiblemember, and means to automatically lock the lever when raised.

10. In a sped changing mechanism, the In testimony that I claim theforegoing combination with two conical pulleys, and a as my invention, lhave signed my name in belt connecting vthe same, of means toautopresence of two subscribing witnesses. maticaily tension ythe beltcomprlsing a roll BERTHOLD GMR. mounted between the pulleys Whose axisis Witnesses; capable of being positioned at an inclination ERNSTFISCHER h t() the axes vof Said pulleys. I AJ-I HER1NEorlj-

